The present invention relates to an aircraft comprising an improved connection zone between a front beam and a front lower fuselage section.
As illustrated in FIG. 1, an aircraft 10 comprises a fuselage 12 having several sections which are arranged at the front and at the rear of a central wing box 14 which allows the wing unit of the aircraft to be connected to the fuselage thereof. The aircraft also comprises a front beam 16 which ensures structural continuity between the sections arranged at the front and at the rear of the central wing box.
In this manner, the end of the front beam 16 is connected to a stiffened panel which forms a portion of the fuselage which is also referred to as the front lower fuselage section 18.
According to an embodiment illustrated in FIG. 2, the front beam 16 comprises a lower panel 20 which is stiffened using T-shaped stringers 22 whose head of the T is pressed against the inner face of the lower panel 20 and side panels 24 which are substantially mutually parallel and parallel with the T-shaped stringers 22 which extend in planes which are substantially orthogonal with respect to the surface of the lower panel 20. The T-shaped stringers 22 and the bases of the side panels 24 do not extend beyond the edge forming the front end of the lower panel 20.
As illustrated in FIG. 3, the front lower fuselage section 18 comprises a panel 26 which is stiffened using T-shaped stringers 28 whose head is pressed against the inner face of the panel 26. The T-shaped stringers 28 do not extend beyond the edge forming the rear end of the front lower fuselage section 18.
The T-shaped stringers 22, 28 and the side panels 24 are orientated in accordance with the longitudinal direction of the aircraft.
In the region of the connection zone, the structure of the aircraft comprises a reinforcement and sealing frame 30 to which there is secured a sealed wall which is arranged in a transverse plane perpendicular relative to the longitudinal direction. In this instance, this sealed wall is the extension towards the bottom of the front spar of the central wing box.
According to an embodiment of the prior art, the connection between the front beam 16 and the front lower fuselage section 18 is of the hybrid type. In this manner, this connection comprises inside the fuselage titanium fittings which ensure the connection:
between the T-shaped stringers 28, the panel 26 of the front lower fuselage section 18 and the reinforcement frame 30,
between the T-shaped stringers 22, the lower panel 20 of the front beam and the reinforcement frame 30, and
between the side panels 24, the lower panel 20 of the front beam and the reinforcement frame 30.
The connection comprises at the outer side of the fuselage a ferrule of composite material which is in the form of a plate which is pressed in a straddling manner against the outer face of the lower panel 20 of the front beam and the outer face of the panel 26 of the front lower fuselage section.
In order to ensure the transmission of forces, it is necessary to widen the front end of the front beam 16 using two widened portions 32 which are arranged symmetrically at one side and the other of the front beam 16.
This solution therefore leads to the on-board mass being increased.
Document FR-2.922.517 proposes a solution in order to ensure the orientation of the forces between two stiffeners of the skin of the fuselage of an aircraft, which stiffeners are arranged at one side and the other of a sealed wall. According to FIG. 2 of this document, the two stiffeners are connected by means of a batten which comprises a planar central portion which is interposed between the skin of the fuselage and the reinforcement frame and, at one side and the other of this central portion, zones for covering and connection to the stiffeners to be connected. The planar central portion has a small thickness so that it is not necessary to create a cut-out in the sealed wall. However, it must have a large width in order to ensure the transmission of forces between the two stiffeners. The batten comprises at one side and the other of the central portion volumic shapes which define housings in which the stiffeners to be connected are capable of being accommodated and being fixed.
This solution has the advantage of replacing metal fittings with battens of composite material and therefore reducing the on-board mass.
However, this solution requires that the stiffeners be perfectly aligned in the longitudinal direction at one side and the other of the reinforcement frame, which is not necessarily the case between, on the one hand, the T-shaped stringers 22 and the side panels 24 of the front beam 16 and, on the other hand, the T-shaped stringers 28 of the front lower fuselage section 18.
Therefore, the present invention is intended to overcome the disadvantages of the prior art.